A Question About Orbits

[r4pt0r]

I will phrase this best I can, then include a poorly drawn MSPaint drawing to try to explain it better.

A satellite is in polar orbit, with its periapsis exactly between its parent planet and a star, and its apoapsis exactly oposite, on the dark side of its parent planet.

As the planet orbits around the star, what happens to the satellite in relation to the star? Will the Polar orbiting satellite always keep its periapsis right between the star and planet? or will it "slide" to eventually be still polar but now perpendicular to the star?

Hope I worded this properly, been something I think about for a while now.

[Mitchz95]

It would slide and become perpendicular. I've done that kind of thing in KSP before.

The only way (that I know of) to keep it between the star and the planet is if the planet is tidally locked, and the satellite is in an equatorial geostationary orbit.

[r4pt0r]

It would slide and become perpendicular. I've done that kind of thing in KSP before.

I thought that, but wasnt sure if it was a ksp thing because of the SOI system. Thanks.

[Kaos]

Beside of orbit disturbances the plane of the orbit is only shifted parallel. Neither the left image nor the right image matches this situation, but the left one is far closer. I can also not see the matching between text and image. To the text: The orbit will "slide". Well, it stays the same, but the star is at another position seen from the planet.

There can be orbits using orbit disturbances to move the orbit to keep it constant relative to the star, for example the planetary bulge of earth can be used to do this. But that would not appear on perfect round planets.

[Mitchz95]

Forgot one. You could also put the satellite into the planet's L1 Lagrangian point. But it wouldn't be orbiting the planet in that case; it would be orbiting the sun close enough to the planet that its gravity would keep it from drifting away.

[PB666]

Forgot one. You could also put the satellite into the planet's L1 Lagrangian point. But it wouldn't be orbiting the planet in that case; it would be orbiting the sun close enough to the planet that its gravity would keep it from drifting away.

Technically it orbits the planet every year. There is also the L2. Objects at L1 and L2 orbit about a focal point in the L1 and L2; however, and these orbits are very unstable and need considerable station keeping. This is however convienient, because if you placed all the things you want to keep at L2 (an excellent point for observations) they would be all stacked and interfere with each other. If you instead cluster them in a small L2 orbit; however unstable, you can keep the spaced apart from each other in space.

[andrewas]

In reality, Earth's gravity is non spherical, and this causes the orbit to precess. If you choose an appropriate inclination and altitude, the orbit can be made to precess once a year, which will keep your periapsis pointed at the star. This is usually done with earth imaging satellites, so that they get the same angle of illumination with each pass, which makes it easier to assemble mosaics from multiple passes to image a wide area.

[Armchair Rocket Scientist]

I will phrase this best I can, then include a poorly drawn MSPaint drawing to try to explain it better.

A satellite is in polar orbit, with its periapsis exactly between its parent planet and a star, and its apoapsis exactly oposite, on the dark side of its parent planet.

As the planet orbits around the star, what happens to the satellite in relation to the star? Will the Polar orbiting satellite always keep its periapsis right between the star and planet? or will it "slide" to eventually be still polar but now perpendicular to the star?

http://i.imgur.com/9fHl013.png

Hope I worded this properly, been something I think about for a while now.

In theory, it will slide and look like the orbit on the left.

However, in real life a satellite's longitude of ascending node slowly precesses. At least for Earth, there is a set of orbits where the precession rate is exactly 360 degrees per year, meaning the orbital plane stays in the same alignment to the star. These are called Sun-synchronous orbits. These are commonly used by mapping satellites because they can always photograph the target area at the same time of day. Cubesats also love SSOs because they can be placed in a dawn/dusk orbit where the satellite is almost always in sunlight.

[Skyler4856]

No inherent force would cause the satellite to turn, so it would retain orientation.